diff --git a/lib/kolab_sync_data_email.php b/lib/kolab_sync_data_email.php
--- a/lib/kolab_sync_data_email.php
+++ b/lib/kolab_sync_data_email.php
@@ -187,6 +187,8 @@
                 'flagType' => 'FollowUp',
                 'status'   => Syncroton_Model_EmailFlag::STATUS_ACTIVE,
             ));
+        } else {
+            $result['flag'] = new Syncroton_Model_EmailFlag();
         }
 
         // Importance/Priority